Elucidation of Compatibility Interactions of Traditional Chinese Medicines: In Vitro Absorptions Across Caco-2 Monolayer of Coptidis Rhizoma and Euodiae Fructus in Zuojin and Fanzuojin Formulas as A Case

Traditional Chinese medicines are often combined as formulae and interact with each other. As for Coptidis Rhizoma (CR) and Euodiae Fructus (EF), the most classical compatibilities were Zuojin (ZJF) and Fanzuojin formulas (FZJF) with reverse mixture ratios and opposite effects. To compare in vitro absorption interactions between CR and EF, bidirectional transports across Caco-2 cell monolayer of extracts of two formulas and equivalent single herbs were studied. Eighteen alkaloids from CR and EF were determined by liquid chromatography coupled to tandem mass spectrometry. Parameter apparent permeability coefficient (Papp) and efflux rate (ER) values showed that most alkaloids were well or moderately absorbed and six quaternary protoberberine alkaloids from CR had obvious efflux. ZJF compatibilities reduced both Papp BL→AP and ER values of three indole alkaloids, and increased ER values of two quinolone alkaloids from EF. FZJF compatibilities obviously affected the bidirectional Papp values of CR alkaloids, weakened ERs of five protoberberines from CR and enlarged ERs of two quinolones from EF. Conclusions were drawn that different compatibility ratios of CR and EF led to different interactions on the in vitro absorption of alkaloids. The results may provide a good reference for interaction studies on the compatibilities of traditional Chinese medicines. Copyright © 2017 John Wiley & Sons, Ltd.